I recently upgraded my PDA from a Palm 3xe (old) to a (smaller) Tungsten T. I experimented with cases without a belt loop, but ended up with that style again. There are downsides, but you can't beat the security- I've had no problems with the T hitting the floor.

Unfortunately, where the old 3xe case was large enough to conceal a CRKT Sampson's K.I.S.S. folder on the backside under the belt (horizontal carry), the new one is not... leaving me looking for another "executive" carry option (not necessarily for that particular folder). It's difficult to find a carry that will stay invisible from suit-and-tie to polo-shirt and kakhis.